Tag Archive for: Wrapped 14 mm 5 MHz QCM sensor

Publication on AWSensors technology

Kinetic selectivity in metal-organic framework chemical sensors

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Authors: Aleksander Matavž, Margot F. K. Verstreken, Leen Boullart, Max L. Tietze, Masaya Sugihara, Lars Heinke, and Rob Ameloot

Journal: ChemRxiv

Abstract: Selective detection of specific volatile organic compounds (VOCs) is crucial for health, safety, and environmental applications, but current sensors suffer from poor selectivity and struggle to measure specific VOCs in the presence of interfering compounds and water vapor. To address this issue, we introduce the kinetic selectivity achievable in nanoporous crystals, specifically metal-organic frameworks (MOFs), into the domain of chemical sensors. In well-selected MOFs, similar molecules can have diffusivities that differ by orders of magnitude. Measuring these diffusivity values is challenging since conventional methods based on rapid changes in atmosphere composition cannot be used in a sensing context. A novel temperature perturbation method was developed for thin-film capacitive sensors with a MOF dielectric layer to enable diffusivity measurements in a fixed atmosphere. Our approach enabled a single sensor to differentiate and quantify VOCs at ppm concentrations, even in mixtures containing high water vapor concentrations, outperforming a state-of-the-art ten-element sensor array.

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Publication on AWSensors technology

Exploiting the high affinity between cellulose nanofibrils and Aloe vera acemannan to develop elastic, crosslinker-free, all-polysaccharide hydrogels

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Authors: Ngoc Huynh, Lukas Fliri, Juan José Valle-Delgado, Monika Österberg

Journal: International Journal of Biological Macromolecules

Abstract: Plant-based polymers hold promising prospects thanks to their bioactivity, diversity and versatility but they are currently overshadowed by synthetic and animal-derived materials, especially in biomedical applications. In this study, we developed an entirely plant-based hydrogel with improved mechanical performance based on TEMPO-oxidized cellulose nanofibrils (TCNFs) and the polysaccharide fraction (AVPF) extracted from Aloe vera L. (Aloe barbadensis Miller). The hydrogel blends exhibited excellent viscoelastic properties, minimal shrinkage and a significant increase in compressive modulus (ranging from 2.7 to 13.2 kPa versus 0.8 kPa in single component hydrogels), suggesting a synergistic effect. In-depth analysis of interaction and morphology of the hydrogels by QCM-D, AFM and SEM imaging showed that the observed synergy was the result of the complementary action between the two components and a uniform spatial distribution of the two networks. TCNFs built the rigid skeleton for the hydrogels, while AVPF physically adsorbed on TCNFs, forming a flexible matrix, allowing for better load transfer and dissipation in both static and dynamic loading, leading to a remarkable increase in moduli that surpassed the mere sum of the two individual components. In addition, the obtained hydrogels also showed little to no perceptible shrinkage after drying, unlike the single-component hydrogels made from the initial materials. These hydrogels offer a sustainable and ethical alternative to animal-derived materials, with great potential in biomedical fields.

The full article can be accessed here.

Publication on AWSensors technology

Matrix Metalloproteinase-9 Mediates Endothelial Glycocalyx Degradation and Correlates with Severity of Hemorrhagic Fever with Renal Syndrome

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Authors: Chloé Jacquet. Rasmus Gustafsson, Ankit Kumar Patel, Magnus Hansson, Gregory Rankin, Fouzia Bano, Julia Wigren Byström, Anders Blomberg, Johan Rasmuson, Simon Satchell, Therese Thunberg, Clas Ahlm, Marta Bally, Anne-Marie Fors Connolly

Journal: medRxiv Preprint

Abstract: Hemorrhagic fever with renal syndrome (HFRS) caused by Puumala virus (PUUV) leads to vascular dysfunction contributing to acute kidney injury and pulmonary complications. The endothelial glycocalyx (eGLX) is crucial for vascular integrity, and its degradation may exacerbate disease severity. In this study, we examined the association between eGLX degradation and renal and pulmonary dysfunction in 44 patients with laboratory-confirmed PUUV infection. We measured plasma levels of eGLX degradation markers—syndecan-1, heparan sulfate, soluble thrombomodulin, and albumin— and found that these correlated with severe acute kidney injury and the need for oxygen therapy. In vitro experiments showed that matrix metalloproteinase-9 (MMP-9) and heparanase can degrade eGLX components, but albumin at physiological concentrations can mitigate this degradation and protect endothelial barrier function. These findings indicate that eGLX degradation contributes to HFRS pathogenesis and suggest that targeting the eGLX could be a therapeutic strategy to improve patient outcomes.

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Publication on AWSensors technology

Revisiting the Charging Mechanism of α-MnO2 in Mildly Acidic Aqueous Zinc Electrolytes

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Authors: Lang Yuan Wu, ZhiWei Li, YuXuan Xiang, WenDi Dong, XiaoDong Qi, ZhenXiao Ling, YingHong Xu, HaiYang Wu, Mikhael D. Levi, Netanel Shpigel, XiaoGang Zhang

Journal: Small 

Abstract: In recent years, there have been extensive debates regarding the charging mechanism of MnO2 cathodes in aqueous Zn electrolytes. The discussion centered on several key aspects including the identity of the charge carriers contributing to the overall capacity, the nature of the electrochemical process, and the role of the zinc hydroxy films that are reversibly formed during the charging/discharging. Intense studies are also devoted to understanding the effect of the Mn2+ additive on the performance of the cathodes. Nevertheless, it seems that a consistent explanation of the α-MnO2 charging mechanism is still lacking. To address this, a step-by-step analysis of the MnO2 cathodes is conducted. Valuable information is obtained by using in situ electrochemical quartz crystal microbalance with dissipation (EQCM-D) monitoring, supplemented by solid-state nuclear magnetic resonance (NMR), X-ray diffraction (XRD) in Characterization of Materials, and pH measurements. The findings indicate that the charging mechanism is dominated by the insertion of H3O+ ions, while no evidence of Zn2+ intercalation is found. The role of the Mn2+ additive in promoting the generation of protons by forming MnOOH, enhancing the stability of Zn/α-MnO2 batteries is thoroughly investigated. This work provides a comprehensive overview on the electrochemical and the chemical reactions associated with the α-MnO2 electrodes, and will pave the way for further development of aqueous cathodes for Zn-ion batteries.

 

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